In a double walled combustor of a gas turbine engine it is known to provide an inner wall which comprises heat resistant tiles with pedestals, which extend toward the outer wall thereby improving heat removal by a cooling air flow between the walls.
Tiles are typically formed from high temperature resistant nickel alloys which are secured to the outer wall by studs integral to the tile, washers and nuts.
Combustors are required to operate at even higher temperatures to increase efficiency of the engine. However, in order to reduce emissions from the engine, more and more of the air flow through the engine is required to be used in the combustion process leaving less air available for use as a coolant of the combustor walls.
It is desirable to use ceramic technology which can resist higher temperatures than the high temperature resistant nickel alloys. However, these ceramics are brittle in structure and are not suitable to be secured in position using the current practice.
In known ceramic liners, such as U.S. Pat. No. 5,553,455 and U.S. Pat. No. 5,957,067, the tiles making up the liner are relatively small and are generally fastened to the outer wall of the combustor by a single pin or attachment feature. In U.S. Pat. No. 5,957,087 a ceramic pin extends through an aperture in the ceramic tile and through a corresponding aperture in the metallic combustor wall and is secured by an expansion resistant fastening. In U.S. Pat. No. 5,553,455 a ceramic tile is provided with a centrally arranged integral ceramic projection that is inserted through and secured by an aperture in a glass ceramic composite support plate.